Cervical collars have been used by physicians and emergency medical technicians for a number of years. Such devices provide initial support of the head in a neutral position. The fundamental task of any cervical collar is to geometrically constrain the wearer's head relative to his neck and back to minimize further (and possibly damaging) movement. In order to meet this goal, the collar must be sized so as to accommodate the geometrical parameters presented by the wearer, such as the circumference of his neck and his neck length--the distance between the wearer's mandible and the top of the wearer's shoulder (at the trapezius muscle). If the collar is not properly fitted to the wearer, the wearer's head may not be supported in a neutral position with the proper degree of support against unwanted movement.
Variations of neck circumference can be dealt with in an economical manner by various strapping systems now on the market, such as that set forth in U.S. Reissue Patent No. 32,219 to Garth. More problematic is accommodating the differences in neck lengths, that is, the range of mandible-shoulder distances that are typically encountered. One solution to this problem is to provide collars of various sizes. Many manufacturers use this technique. It is common for a manufacturer to produce four different sizes to accommodate the differences among adults. Unfortunately, stocking multiple sizes of collars can be unwieldy, and adds to inventory costs. In an emergency response environment such as in an ambulance, space is at a premium and stocking multiple sizes requires additional space, which is difficult to accommodate. Even where such space is available, the inexperienced technician may inadvertently select the wrong size of collar, or simply may not have the correct size of collar on hand, and attempt to fit a collar of the wrong size to the wearer with harmful effect.
There is, therefore, a need for a single cervical collar that can accommodate a variety of wearer sizes, including variation in neck length, so as to minimize the storage and transport space requirements. To further minimize storage space required of such a collar, it would ideally be generally flat (and stackable) in its stored state.
It is known to provide a collar that has a height-adjustable feature, and such is shown in a collar manufactured by the Sure-Loc company under the trade-name Sure-Loc. Unfortunately, this collar does not provide adequate support of both the mandible and mastoid process across its adjustment range, with the result that it permits lateral and rotational motions of the head. There is a need for a cervical collar that in addition to offering multiple sizes in a single collar, provides adequate support to the mandible and the mastoid process across its range of sizes, thereby preventing lateral bending and rotation, in addition to flexion/extension movements of the head.
Another desirable feature of a multi-size collar is that it be easy to use and can be speedily fitted to a wearer. Collars are known that provide variable positioning essentially anywhere between upper and lower limits, but these are often not easy to use. For example, U.S. Pat. No. 2,911,970 to Bartels discloses a collar in which the height is set by tightening screws at any arbitrary point between upper and lower bounds. This collar requires the use of a tool (a screwdriver) to properly fit the collar, which is a drawback in many settings.
A further requirement of a cervical collar is that it can be speedily fitted to a wearer in a risk-free manner. As a practical matter, this suggests a collar that can be sized to a wearer entirely before being fitted to him. Given the chaotic circumstances under which collars must be fitted to wearers in emergency situations, this is of great importance. U.S. Pat. No. 5,520,619 to Martin discloses an adjustable cervical collar in which a complex system of ratchet and pawls provide for highly selective degree of adjustment virtually anywhere within an adjustment range. The collar is fitted to the wearer and adjusted while it is on the wearer by moving the ratchet and pawls relative to one another until the sternum and shoulder brace described therein is set in place against the wearer's sternum. The adjustment of a collar while it is attached to a wearer is potentially harmful to the wearer, as it may occasion further undesirable movement of his head relative to his shoulder. Moreover, the possibility exists that the technician fitting the collar will position it so that it is excessively tight, resulting in additional wearer discomfort that can only be corrected by pulling at the adjustment structure while the collar is attached to the wearer. There remains a need for a collar which can be sized entirely apart from the wearer, and preferably can be readily positioned in one of the standard collar sizes that have won general acceptance in the field.
Cervical collars also must be compatible with other devices that are often used with them, such as extrication devices, backboards, straps, padding, etc., and should not present any hindrances to airway management (which involves the use of face masks, establishment of oral airways, and endotracheal intubation) or access to the throat or spine (establishing surgical airways, palpating the pulse at the carotid arteries, assessing spinal trauma etc.) One of the disadvantages of the aforementioned Sure-Loc collar is that its vertical adjustment mechanism obstructs access to the throat of the wearer. There is a need for a collar which can assume multiple sizes that does not so limit access to the throat of the wearer.
Ease and cost of manufacture are additional and increasingly important considerations, particularly as changes to the economic basis of health care give rise to increasing pressure for lower cost products. Many collars on the market call upon a multiplicity of parts. An example of such a collar is the aforementioned collar described in U.S. Pat. No. 5,520,619 to Martin, which utilizes a variety of separately manufactured parts (such as pawls and rows of ratchet teeth) that increase the manufacturing cost of the article. There remains a need for a cervical collar in which accommodating various sizes does not compromise economy.
Finally, the collar should also be comfortable to the wearer, both for physical and psychological reasons.